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### Topic: Ethanol 99.5 percent to 88  (Read 446 times)

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#### DanjtoUru

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##### Ethanol 99.5 percent to 88
« on: July 10, 2019, 07:41:47 PM »
If I have 99.5 percent pure ethanol, how can I get it to 88 percent?
What amount of water is necessary?

#### Borek

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##### Re: Ethanol 99.5 percent to 88
« Reply #1 on: July 11, 2019, 03:08:55 AM »
You have to show your attempts at solving the problem to receive help, this is a forum policy.

Hint: you will either need densities to solve the problem in terms of solution volumes, or you can reasonably easily solve the problem using solution masses. Imagine starting with 1 kg of solution  - what mass of ethanol does it contain? What should be the mass of the final solution so that given mass of ethanol is 88% of that?
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#### DanjtoUru

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##### Re: Ethanol 99.5 percent to 88
« Reply #2 on: July 11, 2019, 09:35:01 AM »
Sorry for that,
I use C1.V1=C2.V2, i need to make 1000liters of 88% ethanol
The ethanol have 99.5 (that is on the data analysis sheet)
I try with that so i add like 885 lts of ethanol and the rest of water but when i analyze it, it has like 93%

#### Corribus

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##### Re: Ethanol 99.5 percent to 88
« Reply #3 on: July 11, 2019, 10:39:01 AM »
How are you doing your dilution and how are you analyzing the resulting solution?
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

#### Borek

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##### Re: Ethanol 99.5 percent to 88
« Reply #4 on: July 11, 2019, 02:48:19 PM »
I use C1.V1=C2.V2

That works for molar concentrations, not for w/w percentages.
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